JP6712299B2 - Subframe structure - Google Patents

Description

The present invention relates to a subframe structure mounted on a vehicle such as an automobile.

For example, Patent Document 1 discloses a subframe structure including a pair of left and right side members and a center cross member that is disposed between the pair of left and right side members and extends along the vehicle width direction. The pair of left and right side members are arranged so as to be inclined toward the front of the vehicle so as to spread in a reverse V shape.

In the sub-frame structure disclosed in Patent Document 1, a pair of left and right extensions are provided at the joint between the pair of left and right side members and the center cross member. The extension portion is arranged so as to be continuous with the pair of left and right side members and is inclined so as to spread forward toward the front of the vehicle.

Japanese Patent No. 5958005

In the sub-frame structure disclosed in Patent Document 1, the pair of left and right side members and the extension portion are arranged so as to be continuously inclined, and the load is transmitted from the side member to the center cross member via the extension portion. It is possible to transmit efficiently.

However, due to the layout of the space in which the subframes are arranged, the side members and the center cross members may be arranged at positions orthogonal or substantially orthogonal to each other. At that time, even when the extension portion as shown in Patent Document 1 is provided, stress concentration occurs between the side member and the extension portion, or between the extension portion and the center cross member, which causes deformation. Since this is the starting point, it is necessary to increase rigidity and strength.

The present invention has been made in view of the above points, and a subframe structure capable of suppressing the stress concentration at the connecting portion between the vertical member and the cross member and improving the rigidity and strength of the connecting portion. The purpose is to provide.

In order to achieve the above object, the present invention is a subframe structure having a pair of left and right vertical members extending in the vehicle front-rear direction, and a cross member extending along the vehicle width direction between the pair of left and right vertical members. There is provided a gusset that connects each of the vertical members and the cross member, and the gusset has a first inclined surface portion extending in an inclined shape between the vertical member and the cross member, and the cross member is the have a second inclined surface portion continuous with the first inclined surface portion, wherein the cross member extends along the vehicle longitudinal direction, and a recess which is recessed downward is formed, the second inclined surface is characterized Rukoto from the bottom portion of the recess not extend toward the vehicle front end portion of the first inclined surface portion.
Furthermore, the present invention is a sub-frame structure having a pair of left and right vertical members extending in the vehicle front-rear direction, and a cross member extending along the vehicle width direction between the pair of left and right vertical members. A gusset for connecting the cross member to the cross member, the gusset having a first inclined surface portion extending in an inclined shape between the vertical member and the cross member, and the cross member being provided on the first inclined surface portion. A collar member having a continuous second inclined surface portion and vertically connecting the inside of the closed cross section of the cross member is provided, and the collar member includes the first inclined surface portion and the second inside of the closed cross section of the cross member. It is characterized in that it is arranged between the inclined surface portion.

According to the present invention, it is possible to obtain a sub-frame structure capable of suppressing the stress concentration at the connecting portion between the vertical member and the cross member and improving the rigidity and strength of the connecting portion.

FIG. 3 is a perspective view of a vehicle rear portion in which the rear sub-frame according to the embodiment of the present invention is incorporated, as seen obliquely from above. It is a top view of the rear sub-frame shown in FIG. It is a top view of a rear sub-frame which shows the state which removed the 1st-3rd vibration isolator from the state shown in FIG. FIG. 4 is an enlarged vertical sectional view taken along line IV-IV of FIG. 3. (A) is a plan view showing a state where the inclined surface portion provided on the front cross member and the inclined surface portion provided on the gusset are continuous, and (b) is a inclined surface portion and gusset of the front cross member shown in (a). FIG. 3 is a perspective view of the inclined surface portion of FIG. It is an expanded longitudinal cross-sectional view along the VI-VI line of FIG. It is an exploded perspective view showing the attachment state of the 1st color member and the 2nd color member.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a perspective view of a rear portion of a vehicle in which a rear subframe according to an embodiment of the present invention is incorporated, as viewed obliquely from above, FIG. 2 is a plan view of the rear subframe shown in FIG. 1, and FIG. It is a top view of a rear sub-frame which shows the state which removed the 1st-3rd vibration isolator from the state shown. In each figure, "front and rear" indicates the vehicle front-rear direction, "left and right" indicates the vehicle width direction (horizontal direction), and "up and down" indicates the vehicle vertical direction (vertical vertical direction).

As shown in FIG. 1, a rear sub-frame (sub-frame) 10 according to the embodiment of the present invention is arranged behind the vehicle. The rear sub-frame 10 is attached to the lower side of a pair of left and right rear side frames (not shown) extending along the vehicle front-rear direction. The rear sub-frame 10 supports a rear wheel suspension device (not shown), and also mounts a power unit (driving source such as a motor or an engine) P via first to third anti-vibration devices 12, 14 and 16 described later. I support you.

As shown in FIGS. 2 and 3, the rear sub-frame 10 includes a pair of left and right vertical members 18 and 18 extending along the vehicle front-rear direction, and a pair of left and right vertical members 18 and 18 along the vehicle width direction. And a cross member extending in a horizontal direction. The cross member includes a front cross member (cross member) 20 fixed to the vehicle front side of the pair of left and right vertical members 18, 18 and a rear cross member 22 fixed to the vehicle rear side of the pair of left and right vertical members 18, 18. Have and.

As shown in FIG. 1 and FIG. 2, a pair of left and right vertical members 18, 18 is provided at a connecting portion (connecting portion) of the front cross member 20 to connect the vertical members 18 and the front cross member 20 to each other. Gussets 23, 23 are provided. Each gusset 23 is arranged inside the vertical member 18 in the vehicle width direction on the vehicle rear side of the front cross member 20 at a portion where the vertical member 18 and the front cross member 20 are connected. Each gusset 23 will be described in detail later.

A first anti-vibration device 12 and a second anti-vibration device 14 are arranged on both left and right sides of the front cross member 20 along the vehicle width direction with a predetermined distance therebetween. Further, a third vibration isolation device 16 is arranged substantially at the center of the rear cross member 22 along the vehicle width direction. The power unit P is supported so as to be capable of floating at three points via the first to third vibration isolation devices 12, 14, 16 arranged on the front cross member 20 and the rear cross member 22, respectively.

Each anti-vibration device 12 (14, 16) has a mount portion 24 configured by a plurality of legs (three legs in the present embodiment). The vibration isolation devices 12 (14, 16) are attached and fixed to the front cross member 20 and the rear cross member 22 via bolts B and nuts N fastened to the mount portion 24 (described later). (See FIG. 7).

The mount portion 24 functions as a “mounting unit for power unit attached to the cross member”. Each of the vibration isolation devices 12 (14, 16) has substantially the same configuration, and by vibrating by a drive unit (not shown), a positive or destructive vibration isolation effect is exerted on a vibration target to be isolated. It is configured as an active vibration control device.

FIG. 4 is an enlarged vertical sectional view taken along line IV-IV of FIG. 3, and FIG. 7 is an exploded perspective view showing a mounting state of the first collar member and the second collar member.

As shown in FIG. 4, the front cross member 20 has an upper wall 20a having a substantially U-shaped vertical cross section and a lower wall 20b having a U-shaped vertical cross section. The left and right lower end portions of the upper wall 20a and the left and right upper end portions of the lower wall 20b are integrally connected to each other. A closed cross section 26 having a closed cross section is provided between the upper wall 20a and the lower wall 20b. Similar to the front cross member 20, the rear cross member 22 is provided with an unillustrated closed cross section having a closed cross section by the upper wall 22a and the lower wall 22b.

In the front cross member 20, a pair of left and right brackets 28, 28 are respectively interposed between the mount portions 24, 24 of the first vibration isolation device 12 and the second vibration isolation device 14 and the front cross member 20, respectively. ing. The brackets 28 are symmetrically configured.

As shown in FIG. 4, a first collar member 38 is provided between the bracket 28 and the front cross member 20. That is, the first collar member 38 having an annular shape is interposed between the lower surface of the bracket 28 and the upper surface of the front cross member 20. The first collar member 38 is provided with a disc portion 42 having a substantially circular cross-section in the axial direction and having a through hole 40 therein, and an upper side flange portion provided on the upper side of the disc portion 42 and radially expanding outward. And 44. The first collar member 38 is made of a metal material and has high rigidity and strength.

In the closed cross section 26 of the front cross member 20, a second collar member (color member) 46 that connects the closed cross section to the upper limit is provided. The second collar member 46 is arranged coaxially with the first collar member 38 along the vertical direction. The lower end surface of the first collar member 38 contacts the upper surface of the upper wall 20a of the front cross member 20, and the upper end surface of the second collar member 46 contacts the lower surface of the upper wall 20a of the front cross member 20. ing. The second collar member 46 is made of a metal material and has high rigidity and strength. In addition, the axis of the second collar member 46 is provided at a position that vertically overlaps the mounting point where the mount portion 24 is mounted on the front cross member 20.

The second collar member 46 has a cylindrical portion 50 in which a through hole 48 is formed and a diameter-expanding flange portion 52. The through hole 40 of the first collar member 38 and the through hole 48 of the second collar member 46 communicate with each other. A lower end portion of the cylindrical portion 50 of the second collar member 46 penetrates the lower wall 20b and is partially exposed to the outside. The enlarged diameter flange portion 52 is provided on the upper end of the cylindrical portion 50, and has an enlarged diameter toward the outer radial direction as compared with other portions of the cylindrical portion 50.

The bolts B fastened to the mount portions 24, 24 of the first and second vibration isolation devices 12, 14 and the brackets 28, 28 and the front cross member 20 are inserted through the through holes 40, 48, respectively. The first collar member 38 and the second collar member 46 are attached to the front cross member 20, respectively. In other words, the first collar member 38 and the second collar member 46 are fastened together with the mount portion 24, the bracket 28, and the front cross member 20 via the bolt B and the nut N (see FIGS. 4 and 7).

5(a) is a plan view showing a state in which the inclined surface portion provided on the front cross member and the inclined surface portion provided on the gusset are continuous, and FIG. 5(b) is a front cross portion shown in FIG. 5(a). It is the perspective view which looked at the sloped part of a member and the sloped part of a gusset from diagonally above.

As shown in FIGS. 5A and 5B, the vehicle rear side of the front cross member 20 has a recess 54 that is recessed downward at the center in the vehicle width direction. An inclined surface portion (second inclined surface portion) 56 is provided on both left and right sides of the recess 54 along the vehicle width direction. The inclined surface portion 56 has an inclined surface 58 that is inclined rearward of the vehicle from the bottom surface portion 55 at the center of the recess 54 toward the vehicle width direction outer side in plan view.

The pair of left and right gussets 23 has a substantially triangular shape in a plan view, and is arranged symmetrically with respect to each other. Each gusset 23 has an inclined surface portion (first inclined surface portion) 60 extending in an inclined shape between the vertical member 18 and the front cross member 20. The inclined surface portion 60 has an inclined surface 66 that inclines rearward from the vehicle rear wall 62 of the front cross member 20 toward the vehicle width direction inner side wall 64 of the vertical member 18. The inclined surface portion 60 of the front cross member 20 extends from the bottom surface portion 55 at the center of the recess 54 toward one end of the inclined surface portion 60 of each gusset 23.

The inclined surface portion 56 of the front cross member 20 and the inclined surface portion 60 of the gusset 23 are formed so as to be substantially flush with each other on the inner surface of the rear sub-frame 10. In addition, the second collar member 46 that vertically connects the inside of the closed cross section 26 is disposed between the inclined surface portion 56 of the front cross member 20 and the inclined surface portion 60 of the gusset 23 (FIG. 5A, FIG. 5(b)).

FIG. 6 is a vertical cross-sectional view taken along the line VI-VI of FIG.

As shown in FIG. 6, each gusset 23 has a U-shaped cross-section portion 68 having a U-shaped cross section along the vertical direction. The U-shaped cross-section portion 68 is configured by integrally joining an upper gusset 70 having a substantially L-shaped cross section and a lower gusset 72 having a substantially L-shaped cross section. On the upper ridge line of the upper gusset 70, a recessed portion 74 that is recessed in an arcuate cross section toward the inside of the gusset 23 is formed. The recess 74 functions as a relief for avoiding interference with the power unit P.

The vehicle rear part in which the rear sub-frame 10 according to the present embodiment is incorporated is basically configured as described above, and its function and effect will be described next.

In the present embodiment, by providing the pair of left and right gussets 23, 23 that connect the pair of left and right vertical members 18, 18 and the front cross member 20, the load transmission between the vertical member 18 and the front cross member 20. The efficiency can be improved. That is, in this embodiment, each gusset 23 has an inclined surface portion 60 extending in an inclined shape between each vertical member 18 and the front cross member 20, and the front cross member 20 is continuous with the inclined surface portion 60 of the gusset 23. It has an inclined surface portion 56. As a result, in the present embodiment, by making the inclined surface portion 60 of the gusset 23 and the inclined surface portion 56 of the front cross member 20 continuous, it is possible to increase the efficiency of load transmission from the gusset 23 to the front cross member 20. As a result, in the present embodiment, it is possible to suppress the stress concentration at the connecting portion between the vertical member 18 and the front cross member 20 and improve the rigidity and strength of the connecting portion.

In other words, in the present embodiment, not only the inclined surface portion 60 is provided for the gusset 23, but also the inclined surface portion 56 is provided for the concave portion 54 of the front cross member 20. Further, in this embodiment, the inclined surface portion 60 of the gusset 23 and the inclined surface portion 56 of the front cross member 20 are configured to be continuous with each other. As a result, in the present embodiment, it is possible to suppress the stress concentration at the connecting portion between the vertical member 18 and the front cross member 20 and improve the rigidity and strength of the connecting portion. As a result, in the present embodiment, due to the layout of the space in which the rear sub-frame 10 is arranged, etc., the vertical member 18 and the front cross member 20 may be arranged at positions orthogonal or substantially orthogonal to each other. Also, the rigidity and strength of the rear sub-frame 10 can be improved.

Further, in the present embodiment, the front cross member 20 is provided with a recess 54 extending along the vehicle front-rear direction and recessed downward. The inclined surface portion 56 of the front cross member 20 extends from the bottom surface portion 55 of the recess 54 toward the vehicle front end portion of the inclined surface portion 60 of the gusset 23. As a result, in the present embodiment, both the effect of avoiding the interference with the power unit P by the recess 54 and the effect of improving the load transmission efficiency from the gusset 23 to the front cross member 20 are provided. It can coexist (be compatible) and harmonize.

Further, in this embodiment, the gusset 23 is provided with a U-shaped cross-section portion 68 having a U-shaped cross section along the vertical direction. As a result, in the present embodiment, the rigidity and strength of the gusset 23 alone can be improved, and the load transmission efficiency can be further improved.

Furthermore, in this embodiment, the gusset 23 includes an upper gusset 70 and a lower gusset 72 each having a substantially L-shaped cross section, and the U-shaped cross-section portion 68 is formed by the upper gusset 70 and the lower gusset 72. .. As a result, in the present embodiment, by dividing the gusset 23 into the upper gusset 70 and the lower gusset 72, the degree of freedom in the shape of the gusset 23 is increased, and the cross-sectional height dimension of the U-shaped cross section 68 can be increased. it can. As a result, in the present embodiment, the moldability of the gusset 23 can be improved, and the improvement of the rigidity and strength of the gusset 23 can be achieved in harmony with each other.

Furthermore, in this embodiment, a second collar member 46 that vertically connects the inside of the closed cross-section portion 26 of the front cross member 20 is provided, and the second collar member 46 includes the inclined surface portion 56 of the front cross member 20 and the gusset 23. And the inclined surface portion 60 (see FIG. 5A and FIG. 5B). In the present embodiment, the portion between the inclined surface portion 56 of the front cross member 20 and the inclined surface portion 60 of the gusset 23 where the stress is relatively likely to concentrate in the load transmission path is the second collar member having high rigidity and strength. It can be reinforced by 46. As a result, in the present embodiment, the load transmission efficiency can be further improved, and the rigidity and strength of the rear subframe 10 can be further improved.

Furthermore, in the present embodiment, the mounting portion 24 mounted to the front cross member 20 is provided, and the mounting point A at which the mounting portion 24 is mounted to the front cross member 20 is the vertical direction with respect to the axis of the second collar member 46. It is provided at a position where they are overlapped with each other (see FIGS. 7 and 5A). In the present embodiment, a portion between the inclined surface portion 56 of the front cross member 20 and the inclined surface portion 60 of the gusset 23 where stress is relatively likely to be concentrated in the load transmission path is reinforced by the attachment point A of the mount portion 24. ing. As a result, in the present embodiment, the load transmission efficiency can be further improved, and the rigidity and strength of the rear subframe 10 can be further improved.

10 Rear subframe (subframe)
18 Vertical member 20 Front cross member (cross member)
23 Gusset 24 Mount part (mount for power unit)
26 Closed Cross Section 46 Second Color Member (Color Member)
54 recessed part 55 bottom part 56 slanted surface part (2nd slanted surface part)
60 Slope (first slope)
68 U-shaped cross section 70 Upper gusset 72 Lower gusset P Power unit A Mounting point

Claims (6)

A sub-frame structure having a pair of left and right vertical members extending in the vehicle front-rear direction, and a cross member extending along the vehicle width direction between the pair of left and right vertical members,
A gusset for connecting each of the vertical members and the cross member,
The gusset has a first inclined surface portion extending in an inclined shape between the vertical member and the cross member,
The cross member may have a second inclined surface portion continuous with the first inclined surface portion,
The cross member is formed with a recess extending downward in the vehicle front-rear direction and recessed downward.
The second inclined surface portion, the sub-frame structure which is characterized that you have extended toward the vehicle front end portion of the first inclined surface from the bottom portion of the recess. In the sub-frame structure according to claim 1 Symbol placement,
The subframe structure, wherein the gusset has a U-shaped cross-section portion having a U-shaped cross section along the vertical direction. The subframe structure according to claim 2 ,
The gusset includes an upper gusset and a lower gusset each having a substantially L-shaped cross section,
The sub-frame structure, wherein the U-shaped cross section is formed by the upper gusset and the lower gusset. The subframe structure according to any one of claims 1 to 3 ,
A collar member is provided for vertically connecting the closed cross section of the cross member,
The sub-frame structure, wherein the collar member is disposed between the first inclined surface portion and the second inclined surface portion within the closed cross section of the cross member. The subframe structure according to claim 4 ,
A power unit mount attached to the cross member,
A sub-frame structure, wherein an attachment point at which the power unit mount is attached to the cross member is provided at a position overlapping the collar member in the vertical direction. A sub-frame structure having a pair of left and right vertical members extending in the vehicle front-rear direction, and a cross member extending along the vehicle width direction between the pair of left and right vertical members,
A gusset for connecting each of the vertical members and the cross member,
The gusset has a first inclined surface portion extending in an inclined shape between the vertical member and the cross member,
The cross member has a second inclined surface portion that is continuous with the first inclined surface portion,
A collar member is provided for vertically connecting the closed cross section of the cross member,
The sub-frame structure, wherein the collar member is disposed between the first inclined surface portion and the second inclined surface portion within the closed cross section of the cross member.

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